Wound cleansing apparatus with stress

Abstract

An apparatus for cleansing wounds with means for stressing the wound bed and optionally tissue surrounding the wound, in which irrigant fluid from a reservoir connected to a conformable wound dressing and wound exudate from the dressing are recirculated by a devise for moving fluid through a flow path which passes through the dressing and a means for fluid cleansing and back to the dressing. The cleansing means (which may be a single-phase, e.g. micro-filtration, system or a two-phase, e.g. dialytic system) removes materials deleterious to wound healing, and the cleansed fluid, still containing materials that are beneficial in promoting wound healing, is returned to the wound bed. The means for stressing the wound bed and optionally tissue surrounding the wound promotes wound healing. The dressing and a method of treatment using the apparatus.

The invention claimed is: 
     
       1. An apparatus for administering negative pressure to a wound, the apparatus comprising:
 a negative pressure source configured to be fluidically connected to a wound dressing placed over a wound; and 
 a controller configured to control the negative pressure source to cause application of a varying negative pressure to the wound in accordance with a sawtooth waveform, the sawtooth waveform varying about a negative baseline pressure between a first negative pressure value and a second negative pressure value, the first negative pressure value different from the second negative pressure value. 
 
     
     
       2. The apparatus of  claim 1 , wherein the application of the varying negative pressure comprises stressing the wound. 
     
     
       3. The apparatus of  claim 1 , wherein the application of the varying negative pressure comprises maintaining at least one of the first negative pressure value or the second negative pressure value. 
     
     
       4. The apparatus of  claim 1 , further comprising a fluid supply tube configured to be in fluid communication with the wound dressing, the fluid supply tube configured to permit fluid to flow under the wound dressing. 
     
     
       5. The apparatus of  claim 1 , further comprising a fluid offtake tube configured to be in fluid communication with the wound dressing, the fluid offtake tube configured to permit fluid to flow out of the wound. 
     
     
       6. The apparatus of  claim 1 , wherein the varying negative pressure is applied at a controlled frequency. 
     
     
       7. The apparatus of  claim 1 , wherein the wound dressing comprises a conformable wound dressing configured to at least partially cover the wound, the conformable wound dressing configured to form at least a relatively fluid tight seal around at least a portion of the wound. 
     
     
       8. The apparatus of  claim 7 , wherein the conformable wound dressing is configured to maintain negative pressure under the dressing. 
     
     
       9. A method of treating a wound, comprising:
 controlling a negative pressure source to apply a varying negative pressure to the wound in accordance with a sawtooth waveform, wherein the negative pressure source is configured to be fluidically connected to a wound dressing placed over the wound, 
 wherein the sawtooth waveform varies about a negative pressure baseline pressure between a first negative pressure value and a second negative pressure value different from the first negative pressure value. 
 
     
     
       10. The method of treating a wound of  claim 9 , wherein applying the varying negative pressure further comprises stressing the wound. 
     
     
       11. The method of treating a wound of  claim 9 , wherein applying the varying negative pressure further comprises maintaining at least one of the first negative pressure value or the second negative pressure value. 
     
     
       12. The method of treating a wound of  claim 9 , further comprising providing fluid under the wound dressing. 
     
     
       13. The method of treating a wound of  claim 9 , wherein the varying negative pressure is applied at a controlled frequency. 
     
     
       14. The method of treating a wound of  claim 9 , wherein the wound dressing comprises a conformable wound dressing configured to at least partially cover the wound, the conformable wound dressing configured to form at least a relatively fluid tight seal around at least a portion of the wound.